@appearhere/react-stickynode

react-stickynode

A performant and comprehensive React sticky component.

A sticky component wraps a sticky target and remains the target in viewport as an user scrolls the page. Most sticky components handle the case where the sticky target is shorter then viewport, but not the case where a sticky target taller then viewport. The reason is the behavior expectation and implementation is much more complicated.

react-stickynode handles not only regular case but the long sticky target case in a natural way. In regular case, when scrolling page down, react-stickynode will stick to the top of viewport. But in the case of taller sticky target, it will scroll along with the page until its bottom reaches the bottom of viewport. In other words, it looks like the bottom of viewport pulls the bottom of a sticky target down when scrolling page down. On the other hand, when scrolling page up, the top of viewport pulls the top of a sticky target up.

This behavior gives the content in a tall sticky target more chance to be shown. This is especially good for the case where many ADs are in the right rail.

Another highlight is that react-stickynode can handle the case where a sticky target uses percentage as its width unit. For a responsive designed page, it is especially useful.

Features

• Retrieve scrollTop only once for all sticky components.
• Listen to throttled scrolling to have better performance.
• Use rAF to update sticky status to have better performance.
• Support top offset from the top of screen.
• Support bottom boundary to stop sticky status.
• Support any sticky target with various width units.

Usage

The sticky uses Modernizr csstransforms3d and prefixed features to detect IE8/9, so it can downgrade not to use transform3d.

http://modernizr.com/download/?-csstransforms3d-prefixed

import Sticky from 'react-stickynode';

<Sticky enabled={true} top={50} bottomBoundary={1200}>
    <YourComponent/>
</Sticky>

import Sticky from 'react-stickynode';

<Sticky top='#header' bottomBoundary='#content'>
    <YourComponent/>
</Sticky>

Props

• enabled {Boolean} - The switch to enable or disable Sticky (true by default).
• top {Number/String} - The offset from the top of window where the top of the element will be when sticky state is triggered (0 by default). If it is a selector to a target (via querySelector()), the offset will be the height of the target.
• bottomBoundary {Number/String} - The offset from the top of document which release state will be triggered when the bottom of the element reaches at. If it is a selector to a target (via querySelector()), the offset will be the bottom of the target.
• innerZ {Number/String} - z-index of the sticky
• enableTransforms {Boolean} - Enable the use of CSS3 transforms (true by default).
• activeClass {String} - Class name to be applied to the element when the sticky state is active (active by default).
• releasedClass {String} - Class name to be applied to the element when the sticky state is released (released by default).
• onStateChange {Function} - Callback for when the sticky state changes. See below.
• shouldFreeze {Function} - Callback to indicate when the sticky plugin should freeze position and ignore scroll/resize events. See below.

Handling State Change

You can be notified when the state of the sticky component changes by passing a callback to the onStateChange prop. The callback will receive an object in the format {status: CURRENT_STATUS}, with CURRENT_STATUS being an integer representing the status:

• 0 (STATUS_ORIGINAL) - The default status, located at the original position.
• 1 (STATUS_RELEASED) - The released status, located at somewhere on document, but not default one.
• 2 (STATUS_FIXED) - The sticky status, located fixed to the top or the bottom of screen.

You can access the statuses as static constants to use for comparison.

import Sticky from 'react-stickynode';

const handleStateChange = (status) => {
    if (status.status === Sticky.STATUS_FIXED) {
        console.log('the component is sticky');
    }
}

<Sticky onStateChange={handleStateChange}>
    <YourComponent/>
</Sticky>

Freezing

You can provide a function in the shouldFreeze prop which will tell the component to temporarily stop updating during prop and state changes, as well as ignore scroll and resize events. This function should return a boolean indicating whether the component should currently be frozen.

Install & Development

Install

npm install react-stickynode

Unit Test

grunt unit

License

This software is free to use under the BSD license. See the LICENSE file for license text and copyright information.